It was 100 years ago this week that the liner set sail from Southampton for New York on her maiden voyage. Maritime officials and experts have warned the vessel, which hit an iceberg in April 1912 is rusting away at the bottom of the ocean.

The US Coast Guard recently wrote to the International Maritime Organisation asking for a ban on ships dropping rubbish or releasing sewage within 10 nautical miles of the site.

Mr Ballard, a professor of oceanography at the University of Rhode Island, said last week that he will apply for a permit from US authorities to conduct an ambitious operation nearly 2 1/2 miles beneath the surface.

He has seen significant decay in the wreck that he found in 1985 as bacteria colonies, possibly fed by human waste and rubbish, have eaten away at the steel hull.

He said the technique was needed "so the hull doesn't splay open and expose the highly preserved interior with its precious contents".

Mr Ballard also proposes robot be used as "sentries" to monitor the visits by tourist submersibles that he is convinced have damaged the wreck. The Titanic is "being killed by love", he said last week.

Describing the wreck as "under siege" by natural forces, careless visitors and rogue salvage operators, he outlines his fears that it will not survive another 100 years in Save the Titanic, a documentary to be broadcast on the National Geographic cable channel this week.

But Rob McCallum, the general manager of Deep Ocean Expeditions which will this summer run a $60,000-a-head cruise and submarine trip to the site, said it was "nonsense" to suggest that the $50 million submersibles were knocking into the wreck.

He said the vessels effectively "hovered" weightlessly while the tourists looked at the remains. "They are delicate, so a pilot who 'drove around bashing into things' would probably come to grief pretty quickly," he told The Daly Telegraph.

"The biggest fear any sub pilot has is entanglement, so they keep away from the wreck and usually face towards it so that they can keep an eye on it so as to gauge relative position and the current."

He said the Titanic was deteriorating because it is a metal ship that has been lying in the ocean for 100 years rather than because of the occasional visit by a small tourist submarine.

In what are effectively unpoliced waters, there are also fears that unscrupulous salvage teams with small remotely operated underwater vehicles are plundering the site.

Sen John Kerry recently introduced a bill into the US Congress designed to toughen up protection of the site.

James Delgado, chief of the maritime heritage office at the National Oceanic and Atmospheric Administration said: "The Titanic can be a model for how humanity treats the world's underwater cultural heritage. But we cannot do nothing."